I hope you won't mind @starbreaker if I make my way across the bar and sidle up next to you. I couldn't help but overhear your conundrum, and well, suffice it to say I have my own narcissistic tyrant of a mother and hope you'll indulge me in another bar custom: unsolicited advice. Not my business, of course, but I've been where you are and I know the landscape.
You'd think that cutting contact would help, and it does, but not in the ways you're imagining. What happens after you cut contact isn't a montage of riding a motorcycle down a desert highway while The Stones play in the background. It's grief, not for what you had, but for what should have been. It's sitting with all of those moments in which your parents failed you and grieving for the child you were while also offering your current self what that child never had.
It's worth it, of course, but it takes a lot of work to get to worth it, and a lot of courage to set the first foot down that path. What you find at the end of that path, if you're lucky, persistent, and don't catch too much bad weather, is understanding. It's bittersweet in your parents' absence, but it makes the pain of everything they put you through a little more bearable.
That's when you get the motorcycle montage. When you understand why they behave the way they do while still acknowledging that it's not your job to tolerate or help correct that kind of treatment.
My two cents? Do the work toward that sweet, Mojave Desert at sunset scene now, before your mother moves into your house. It won't fix it, and it won't make her behavior okay, but it'll help keep you sane.
@Bartender, another white lady for the gentleman and another sidecar for me, if you please.